How the collection search works
The results list for the collection search only includes the title and a brief summary about each relevant collection even though the entire inventory for each collection has been searched.
The result list for the collection search is organized by relevance. The first collection listed in the search results list has more mentions of your keyword throughout the collection inventory than the second collection on the list, even if your keyword doesn't appear in the title or summary in the search results list.
When you click on the title of a collection in the search results, you will be taken directly to a list of the folder or items in which your keyword does appear. If you click on any of the folders or items on that list, a new browser tab or window will open to display the details of that folder or item.